Labour market marginalization in children of persons with major psychiatric disorders: a Swedish national cohort study
Authors: Ashley E. Nordsletten, Kayoko Isomura, James J. Crowley, Matti Cervin, Henrik Larsson, Paul Lichtenstein, David Mataix‐Cols, Anna Sidorchuk
Journal: World Psychiatry (2023)

Stable employment is consistently and strongly linked to key indicators of life quality and longevity, including physical and mental health, social integration, self-conception and self-fulfilment1. Involuntary exclusion, destabilization, or marginalization from the workforce has negative impacts across these same personal, social and economic domains. These effects may be further compounded by individual features (e.g., poor health, low education) or life stressors (e.g., low socioeconomic status, housing instability) associated with under- or un-employment2. Studies have highlighted a critical role for childhood adversity in influencing occupational trajectories. While the working definition has varied across investigations, there is a generally unified conception of “adversity” as encompassing both economic (e.g., low socioeconomic status) and emotional (e.g., chaotic environment) factors. In acknowledgement of its influence across these factors, it has been common for these definitions to include a measure of parental mental health. Despite this, the relationship of parental mental illness to intergenerational occupational outcomes remains poorly delineated. Previous work has focused primarily on proxy-behaviors associated with parental psychiatric health (e.g., alcohol/drug abuse), and on early-life features associated with future work opportunity (e.g., personality formation, educational attainment)3, 4. We are unaware of any work, to date, that has been powered to longitudinally dissect the relationship between established parental psychiatric diagnosis and objective occupational outcomes in offspring. Further, no work has considered the differential impact of parental diagnostic structure (e.g., mood vs. psychotic disorders; one vs. two affected parents) on these associations. Indeed, non-random mating is common in psychiatric populations5, 6, and likely to have a considerable impact on a range of offspring functional outcomes7. Here, we focused on the following questions: a) Is risk for receipt of disability pension and long-term unemployment increased among the offspring of persons with psychiatric disorders? b) Is this risk further increased if both biological parents have a psychiatric disorder? and c) What role do other individual (e.g., offspring's own mental health) and environmental (e.g., parent's level of education) factors have in this association? Ethical approval for this project was granted by the Regional Ethics Review Board in Stockholm, Sweden. Leveraging linkage of key Swedish national registers, we assembled a cohort of 2,010,587 offspring (from 1,198,151 parental pairs) born in Sweden from January 1, 1973 to December 31, 1993. Using offspring of psychiatrically unaffected parents as a reference (selected in an “uncleaned” manner8), we compared the risks of receiving disability pension and long-term unemployment in offspring of single-affected parents (mother or father) and dual-affected parents (both mother and father) with any of the following eleven major psychiatric disorders: attention deficit/hyperactivity disorder, autism spectrum disorder, Tourette's/chronic tic disorder, substance use disorders, generalized anxiety disorder, major depressive disorder, agoraphobia, social phobia, obsessive-compulsive disorder, schizophrenia and bipolar disorder. The disorders were then clustered into four operational groupings: neurodevelopmental disorders, substance use disorders, emotional disorders, and psychotic disorders (including schizophrenia and bipolar disorder). Within each disorder group, an exposure variable was created to distinguish dual-affected from single-affected pairs: for example, “dual-affected with psychotic disorders” indicates a pair in which both parents have schizophrenia or bipolar disorder (in any combination), while “single-affected with psychotic disorders” indicates a pair in which only one parent has a diagnosis within this disorder group. For offspring outcomes, we estimated the incidence risk ratio (IRR) for disability pension and long-term unemployment across exposure groups. Several covariates were integrated in our models, including key demographic characteristics (base model), with further adjustment for offspring somatic disorders and highest educational level. A fully-adjusted model further controlled for parent's highest educational level and his/her receipt of disability pension/long-term unemployment. Most covariates were defined over the full study period (e.g., full length of follow-up), with a minority adapted to capture impacts at salient timepoints. In sensitivity analyses, we explored the impact of offspring's own psychiatric health by excluding offspring with any of the above-mentioned disorders. We also re-ran the main analyses using a “cleaned” comparison group, in which neither parent had any of the eleven relevant lifetime psychiatric diagnoses. For each outcome, we fitted modified Poisson regression models with robust standard errors9, using person-years as the offset term to address different follow-up times among participants, and clustering by family identification number to account for non-independence of repeated observations within families. Compared to offspring of unaffected parents, individuals with one affected parent had a significantly increased risk of disability pension receipt, when accounting for demographic characteristics (IRR=1.88, 95% CI: 1.84-1.91, p<0.001; in 332,357 offspring of single-affected pairs vs. 1,641,244 offspring of unaffected pairs). The risk was doubled in offspring of dual-affected parents (IRR=2.84, 95% CI: 2.73-2.95, p<0.001; in 36,986 offspring of dual-affected pairs vs. 1,973,601 offspring of unaffected pairs). While all parental psychiatric disorders showed a significant association with offspring disability pension risk, the highest risk was observed in the offspring of parents affected with neurodevelopmental disorders (single-affected: IRR=3.36, 95% CI: 3.20-3.54, p<0.001; dual-affected: IRR=7.25, 95% CI: 5.68-9.26, p<0.001) and psychotic disorders (single-affected: IRR=2.11, 95% CI: 2.03-2.19, p<0.001; dual-affected: IRR=5.31, 95% CI: 4.33-6.52, p<0.001). Results were robust to further adjustment for offspring somatic disorders and education (single-affected with any disorders: IRR=1.73, 95% CI: 1.69-1.76, p<0.001; dual-affected with any disorders: IRR=2.38, 95% CI: 2.28-2.47, p<0.001) and for parental socioeconomic characteristics (IRR=1.40, 95% CI: 1.38-1.43, p<0.001; and IRR=1.60, 95% CI: 1.54-1.67, p<0.001, respectively). Results by parental disorder groups were also robust across models. Offspring with one affected parent had a significantly increased risk of unemployment, compared to offspring of unaffected parents (IRR=1.46, 95% CI: 1.45-1.48, p<0.001). This risk was markedly raised among offspring of dual-affected pairs (IRR=1.92, 95% CI: 1.87-1.96, p<0.001). Offspring of parents single- and dual-affected by neurodevelopmental and substance use disorders showed the highest unemployment burden across both the base model and the model controlling for offspring somatic disorders and education. The fully-adjusted model resulted in significant, but attenuated, risks among offspring: IRR=1.21, 95% CI: 1.20-1.23, p<0.001 (single-affected with any disorders) and IRR=1.34, 95% CI: 1.30-1.38, p<0.001 (dual-affected with any disorders). Corresponding results by parental disorder groups were also attenuated, though the majority of them retained significance. Repetition of analyses in a sub-cohort of offspring free from the diagnosis of interest produced comparable results for both outcomes. Likewise, the use of the “cleaned” comparison group in a sensitivity analysis did not alter the results. Taken together, these results indicate a consistent and profound association between psychiatric history of parents and labour market marginalization in their offspring, which is particularly striking in dual-affected families. Though our primary finding is one of global, relative occupational adversity among the children of all affected parents, variation was further observed by parental diagnosis, with children of families impacted by neurodevelopmental, psychotic and substance use disorders having increased risk for adverse occupational outcomes. Further work will be needed to gain nuanced insight into the mechanisms impeding labour market prospects in these populations, particularly given the limited impact of suspected determinant factors (e.g., child's own psychiatric health) on this association. Our findings suggest that such work should continue to extend consideration of differential risk dynamics by parent diagnosis and, particularly, parental diagnostic structure (e.g., single- vs. dual-affected families), in order to identify subgroups with particular need for preventive and early intervention strategies aimed to increase their chances of labour market participation.